Skip to main content
Builds a new list by adding items to either end of an input list. Use it to fold a value into a list without leaving the data engine — for example, building a list of order lines inside a Flow Each loop.

​
Inputs

  • List — the starting list. Leave unwired, or wire a source that produced nothing, to start from an empty list. A nil value is also treated as empty, and a single value that is not a list is treated as a one-item list (so a scalar such as a first name can start the list).
  • Prepend — item to put at the start of the list. Leave unwired, or wire an empty timeline, to skip prepending.
  • Append — item to put at the end of the list. Leave unwired, or wire an empty timeline, to skip appending.
Connecting both Prepend and Append in the same node is allowed — the prepend item lands first, the append item lands last, all in one shot.

​
Over time

All three inputs are timelines, and the result is one too: one entry for every date on which the list or an item changes, holding the list as it is on that date with the items in effect on that date. A surname change dated next year therefore shows up next year, not today. An item change that leaves the result as it was adds no entry. Before the list’s first entry the list is empty, so only the items are there. With plain values (one entry each, valid since forever) the result is a single entry.

​
Ports